Maybe try this, make a new file called CayenneESP8266WiFiClient.h and use
it instead of CayenneWifiClient.h. I added config to the public calls and directed it to use the Cayenne domain and port. I still think the problem is that the Cayenne functions do not have a handle. Hard to really help you since you haven’t shared your current sketch.

This sketch is an example. I don’t want to amend the main sketch that consist is more than 12 separate files and a hundred of routines.

The idea not to use Wi-Fi connection made by Cayenne is in the following: there is a number of WiFi managers that can provide you with connection setup in a case of non-connected. It is obvious that it is not possible to use them if the sketch uses Cayenne WiFi connection. That’s the reason.